The present invention relates to the field of methods and arrangements that pertain to microwave lenses.
There is sometimes the need to transmit or receive microwave radiation in technical applications. Radar and microwave communication are examples of such technical applications.
Different forms of antenna elements are used to transmit and/or receive microwave radiation. Monopoles, dipoles, horns, resonant slots, microstrip patches or aperture-coupled microstrip antennas are examples of different antenna elements used in this respect.
It is sometimes desirable to be able to influence significantly the microwave radiation that shall be transmitted and/or received by the antenna elements. When receiving, it is sometimes desirable to collect together microwave radiation to the antenna elements. When transmitting, it is sometimes desirable to spread or concentrate the microwave radiation generated by the antenna elements. In order to achieve this type of influence on microwave radiation, it is normal to use microwave lenses that are disposed in the close proximity of the antenna elements such as to influence the microwave radiation in the manner intended by refraction of the microwave radiation. The microwave lenses are produced from a dielectric, such as alumina. An example of a more complicated application of microwave lenses is given by S. Raman et al, xe2x80x9cA W-Band Dielectric-Lens-Based Integrated Monopulse Radar Receiverxe2x80x9d, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, Vol. 46, No. 12, December 1988, where microwave lenses are used to eliminate particular electromagnetic oscillating modes along a surface of a substrate in a receiver of a monopulse radar for the millimetre wave range.
One drawback with microwave lenses, however, is that the arrangement of such lenses is relatively complicated and expensive. It is first necessary to shape the lenses, which is effected by abrasion or moulding. The lenses are then fitted in holders adjacent the antenna elements. The lenses must be positioned very precisely in the holders, because there must be no air gap of any appreciable size between the lenses and the antenna elements, and because the lenses must not come into contact with the antenna elements and therewith possibly damaged.
The present invention mainly addresses the problem of simplifying the arrangement of microwave lenses in particular but not exclusively, when microwave lenses are arranged in the close proximity of antenna elements in devices for transmitting and/or receiving microwave radiation.
In brief, the above defined problem is solved in the following manner. The microwave lens is arranged in the form of a material droplet that refracts microwave radiation. In a liquid state, the droplet assumes a predetermined shape which is determined mainly by outer limitations or boundaries, the amount of material in the droplet, and the properties of the material. The droplet is then allowed to solidify while retaining its assumed shape. The microwave lens can thus be produced very easily, because the lens (droplet) need not be shaped by abrasion, moulding or equivalent processes.
A main object of the present invention is thus to simplify the manufacture of microwave lenses, and the invention includes both methods and devices that are related to this simplified manufacturing process.
More specifically, the aforesaid problem is solved by exemplifying embodiments of the invention.
According to one embodiment of the invention, one or more microwave lenses are provided in the aforesaid manner in connection with antenna elements in the manufacture of a device for transmitting and/or receiving microwave radiation, wherein the invention also relates to such a device.
According to another exemplifying embodiment of the invention, the aforesaid method of arranging microwave lenses is applied in a method manufacturing microwave lenses, wherein the invention also includes microwave lenses obtained in this way.
The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings.